The objectives of the project are to characterize the positional information in the integument of arthropods, and to study how positional information is translated into form. The specific aim is to test and extend the fluid elastic shell model for the shaping of epithelia during development. This model has important implications for the processes which shape epithelia in early stages of human development. Tests of the model will be performed on the hypodermis, the monolayered epithelium underlying the integument of insects and crustaceans. The mechanical properties of the hypodermis will be investigated by deforming vesicles of hypodermis prepared in vitro, and measuring the resulting changes of tissue and cell shape. Implications of the model for the large-scale form of body parts will be tested by grafting patches of integument to ectopic sites in vivo, and characterizing the deformations of tissue and cell shape which occur during the post-operative regulation of pattern and form.